1. Field of the Invention
This invention relates generally to water treatment systems, and more particularly to a water aeration system and method for aerating water in an improved manner utilizing natural forces.
2. Background Art
Most conventional water aeration systems require pumps, compressors, or other machinery that consume energy to operate. While capable of introducing air into the water, air compressors and pumps typically output a low volume of air at a relatively high pressure, rather than a higher volume of lower pressure air more suitable for aeration. Consequently, to provide the desired amount of aerating bubbles, compressors frequently require significant amounts of input energy, which makes their operation expensive. In addition, the use of pistons and other associated moving linkages in air compressors increases noise and the likelihood of component breakdown, possible introduction of hydrocarbons into the water being aerated, and potentially expensive maintenance.
Some systems used in aeration of water employ spargers such as perforated pipe and the like for releasing the oxygen bearing gas into the bottom of a storage tank or holding pond. The dispersion of the released gases from the sparger may be further agitated by rotating vanes or multiple level baffles within the storage tank. For example, an arrangement for introducing the oxygen bearing gas in line with a propeller agitator is shown in U.S. Pat. No. 3,865,721 to Kaelin. Other efforts to directly agitate a fluid by releasing pressurized gas below the fluid surface and into flow directing columns are shown in U.S. Pat. Nos. 1,574,783 to Beth, 3,043,433 to Singer and 3,446,488 to Mail et al.
In providing oxygen for an aerobic system, air flow as is generally measured in cubic feet per minute (cfm) is highly important as it requires approximately 65 cubic feet of air for each pound of oxygen. A traditional rule of thumb relative to mechanical aeration systems is that two pounds of dissolved oxygen (DO) per horsepower hour is the expected level of recovery and the operating costs for such aeration systems has increased as power costs have increased. Further, the power requirements to overcome the hydraulic head of relatively deep containers or storage ponds, such as, up to a depth of about 20 feet often pose further economic disadvantage for the prior art diffuser and sparger systems.
It has also been known to use a pressure differential injector for drawing gas into a liquid stream as is shown in U.S. Pat. No. 1,430,303 to Hartman while similar such injector/mixer apparatus for other applications are shown in U.S. Pat. No. 3,243,046 to Kakumoto et al.
Venturi-type devices for intermingling of gases and fluids, are also known in the art, but have been primarily used for the purpose of agitation accomplished by release of air bubbles at the surface and are not particularly suited for meeting the continuous emulsification and large volume mixing demanded by water treatment facilities.
Accordingly, there has been a continuing need for economic and efficient methods and apparatus of gas/fluid intermingling adequate to meet the demands for odor control as in the use of anaerobic ponds and especially to meet the stringent regulations concerning effluence entering rivers and streams.
The present method and water aeration system utilizes the natural motion of running water and differential pressure to absorb oxygen into a body of water, a system of apparatus that creates turbulence within the body of water to efficiently mix oxygen from the atmosphere with water, and after the creation of the turbulence, passes the aerated water across a paddlewheel to distribute the aerated water evenly throughout a body of water and circulate the water to allow the surface of the body of water to absorb even more oxygen from the air above the water surface.
The present method and water aeration system may be used for aerating wastewater; in aquaculture applications to sustain marine life in lakes, ponds and other bodies of water; in agricultural applications, and in many other applications where a sufficient quantity of oxygen in the water is essential.
The present method and water aeration system does not require pumps, compressors, or other machinery that consume energy to operate, and thus conserves energy, and is environmental friendly. The system utilizes primarily PVC piping and thereby significantly reduces corrosion and maintenance costs, compared to conventional aeration systems.